The present invention relates to a two-way orifice check valve device, and more particularly, to a two-way orifice check valve device for a hydraulic circuit, in which the control pressure is stabilized during the engagement and release of a clutch, and that simplifies the hydraulic circuit controlling the clutch.
Generally, in a hydraulic circuit for controlling the actuation of a friction element such as a clutch, a structure prevents the abrupt engagement of the friction element. But a conventional hydraulic circuit may include many individual check valves, orifices, pressure relief valves, and the required connecting conduits. Each of these require machining and assembly. Accordingly, the conventional hydraulic circuit is unnecessarily complicated, large, and costly.
In accordance with a preferred embodiment of the present invention, the two-way orifice check valve for a hydraulic circuit includes an orifice check valve and a pressure relief valve in a single unit. The orifice check valve includes: a body part movably installed within a first pressure chamber of an inlet conduit; first and second orifices formed on both ends of the body part respectively; a conduit communicating between the first and second orifices; a plurality of elongate projections formed around the outside circumference of the body part, for forming a plurality of flow paths between the body part and the first pressure chamber; and an access allowing communication between the elongate projections and the conduit. The pressure relief valve includes: a second pressure chamber communicating to an outlet conduit and disposed adjacently to the first pressure chamber; and a valve element having an axial flow path disposed within the second pressure chamber and elastically supported by a return spring.
In a preferred embodiment of the invention a two-way orifice check valve device includes a body slidably installed within a first pressure chamber. The body slides between a first sealing position against an inlet conduit in response to a releasing fluid flow and a moveable sealing position against a valve element in response to an engaging fluid flow. The body includes a first orifice through which the entire releasing fluid flow is directed when the body is in the first position. The body also includes a second orifice through which at least part of the engaging fluid flow is directed when the body is in the second position. A channel or a plurality of channels along the body connect to an access within the body that allows fluid flow from the channel to enter a conduit within the body. This conduit leads to the first and second orifices. The channel is dimensioned and configured to allow the body to seat against the first pressure chamber when the body is in the first position. A spring seats the valve element against a third position (adjacent the first pressure chamber) during the releasing fluid flow and during an engaging fluid flow that is at less than a relief pressure. The valve element has a flow path through which the releasing fluid flow is directed before it flows though the first orifice and through which the engaging fluid flow is directed after flowing through the second orifice. When the engaging fluid flow is greater than the relief pressure the valve element moves from the third position and allows the engaging flow to bypass the second orifice, although some of the engaging fluid flow will still flow through the second orifice.